Alternative Pathway is Involved in Nitric Oxide-Enhanced Tolerance to Cadmium Stress in Barley Roots
Alternative Pathway is Involved in Nitric Oxide-Enhanced Tolerance to Cadmium Stress in Barley Roots
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DOI：
10.3390/plants8120557
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发表时间：
2019-12-01
期刊：
影响因子：
4.5
通讯作者：
Bi, Yurong
中科院分区：
文献类型：
--
作者：
He, Li;Wang, Xiaomin;Bi, Yurong
替代途径（alternative pathway，AP）已被广泛认为参与增强对各种环境胁迫的耐受性。本研究以青稞（昆轮14）和大麦（甘啤6）为材料，研究了酸性磷酸酶（AP）在镉（Cd）胁迫下的响应。结果表明，镉胁迫下，两个大麦品种叶片丙二醛（MDA）含量和电解质渗漏率（EL）水平均升高。Cd胁迫下，昆伦14的交替氧化酶（AOX）基因（主要是AOX 1a）、AP能力（V-alt）和AOX蛋白量的表达量明显增加，施用NO供体硝普钠（SNP）后，这些参数进一步增强。此外，Cd处理使两个大麦品种根系中H2 O2和O-2（-）含量升高，外源SNP则显著缓解了Cd处理对大麦根系中H2 O2和O-2（-）含量的影响。然而，这种缓解作用加重水杨羟肟酸（SHAM，AOX抑制剂），表明AP有助于NO增强镉胁迫耐受性。进一步的研究表明，SHAM应用对活性氧（ROS）相关的清除酶和抗氧化剂的影响很小。这些结果表明，AP发挥了不可或缺的功能，在NO增强镉胁迫下两个大麦品种。AP主要负责调节ROS的积累，维持氧化还原状态的稳态。
Alternative pathway (AP) has been widely accepted to be involved in enhancing tolerance to various environmental stresses. In this study, the role of AP in response to cadmium (Cd) stress in two barley varieties, highland barley (Kunlun14) and barley (Ganpi6), was investigated. Results showed that the malondialdehyde (MDA) content and electrolyte leakage (EL) level under Cd stress increased in two barley varieties. The expressions of alternative oxidase (AOX) genes (mainly AOX1a), AP capacity (V-alt), and AOX protein amount were clearly induced more in Kunlun14 under Cd stress, and these parameters were further enhanced by applying sodium nitroprussid (SNP, a NO donor). Moreover, H2O2 and O-2(-) contents were raised in the Cd-treated roots of two barley varieties, but they were markedly relieved by exogenous SNP. However, this mitigating effect was aggravated by salicylhydroxamic acid (SHAM, an AOX inhibitor), suggesting that AP contributes to NO-enhanced Cd stress tolerance. Further study demonstrated that the effect of SHAM application on reactive oxygen species (ROS)-related scavenging enzymes and antioxidants was minimal. These observations showed that AP exerts an indispensable function in NO-enhanced Cd stress tolerance in two barley varieties. AP was mainly responsible for regulating the ROS accumulation to maintain the homeostasis of redox state.